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French Onion Bites

These French onion bites offer all the rich, comforting flavours of the classic Parisian soup in a sophisticated, bite-sized format. This vegetarian appetiser features deeply caramelised onions deglazed with white wine, served on crisp baguette crostini and finished with a generous layer of melted Gruyère cheese. The combination of sweet, savoury onions and nuttiness from the cheese creates a truly indulgent snack that is perfect for autumn entertaining or as a festive dinner party starter.

Quick to assemble once the onions are prepared, these crostini are an excellent choice for hosting as the topping can be made in advance. Serve them warm from the grill while the cheese is still bubbling to ensure the best texture and flavour. They pair beautifully with a chilled glass of dry white wine or a light sparkling cider, making them a versatile addition to any vegetarian canapé selection.

Continue reading below

Ingredients for French Onion Bites

  • 36 thin (1/4-inch) slices of baguette (from 1 baguette)

  • 1 tablespoon unsalted butter

  • 1 tablespoon olive oil

  • 2 large onions, chopped (about 600g )

  • 1 garlic clove, lightly crushed

  • 1 small bay leaf

  • 1 sprig fresh thyme

  • 60ml white wine

  • 350ml finely shredded Gruyere (using a microplane, about 90g )

Preheat oven to 191°C with rack in middle.

Arrange slices on a large baking sheet and bake in oven until golden, about 8 minutes. Let cool.

Meanwhile, heat butter and oil in a 10-inch heavy skillet over medium heat until butter is melted, then cook onion, garlic, bay leaf, and thyme with 1/2 teaspoons salt and 1/4 teaspoons pepper, covered, stirring occasionally, 10 minutes.

Uncover skillet and cook, stirring occasionally, until deep golden, about 10 to 15 minutes more. Add wine and cook until entirely evaporated, 1 to 2 minutes. Discard garlic clove, bay leaf, and thyme. Transfer to a small bowl and keep warm, covered.

Preheat grill.

Arrange toasts on a large baking sheet, then top each with a rounded teaspoon of caramelized onions and sprinkle generously with shredded Gruyere. Grill 3- to 4-inches from heat until cheese is melted, 1 to 2 minutes (watch carefully).

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.

Article history

The information on this page is peer reviewed by qualified clinicians.

  • 28 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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